LOS ANGELES, Sept. 18 (AScribe Newswire) -- Advances in imaging may allow physicians to detect smaller lung cancers than ever before. But does screening for lung cancer before symptoms appear using either conventional X-rays or the latest in imaging techn

Today, researchers at UCLA's Jonsson Cancer Center and nationwide are launching the National Lung Screening Trial (NLST) to find out. A joint study of the American College of Radiology Imaging Network (ACRIN) and the Prostate, Lung, Colorectal and Ovarian (PLCO) cancer screening trial, the NLST is the largest clinical trial ever funded by the National Cancer Institute for lung cancer screening. Nationwide, the study seeks to enroll 50,000 healthy current or former smokers at risk of lung cancer. The trial is being conducted at UCLA and 29 other sites nationwide and seeks to determine which screening test, chest X-ray or chest CT, is more effective at reducing lung cancer deaths. At UCLA's Jonsson Cancer Center, the only California site currently offering the screening study, researchers hope to enroll 2,000 to 4,000 current and former smokers within the next 18 months. "This is the first national trial of this scale designed to determine which screening test will better reduce lung cancer mortality," said Dr. Denise Aberle, the ACRIN/NLST national principal investigator, lead investigator at UCLA and a researcher at the Jonsson Cancer Center. "Our hope is that this study will lead to saving lives." Lung cancer kills more Americans every year than breast, prostate, colon and pancreas cancers combined, and is responsible for about 28 percent of all cancer deaths in the United States. This year alone, more than 169,000 Americans will be diagnosed with lung cancer. Of those, 154,900 will die, according to the American Cancer Society. And yet, there is currently no standard approach to lung cancer screening, Aberle said. Chest X-rays produce a two-dimensional view of the chest and can detect abnormalities the size of a quarter or smaller using radiation exposures that are among the lowest in medical imaging. With low-dose spiral CT, the patient moves on a table through a doughnut-shaped structure that acquires views from all angles. These views are combined to produce a three-dimensional image of the chest. With CT scanning, dime-sized abnormalities can be detected, although at somewhat higher levels of radiation. "Right now, our understanding of lung cancer screening using either modality is incomplete," said Aberle, also a professor and vice-chairman of research in the Department of Radiological Sciences at UCLA. The benefits of chest X-ray versus no screening at all are currently being studied in a separate part of the PLCO trial. Low-dose spiral CT is a newer approach to lung cancer screening, and has been lauded by some health professionals because of its ability to detect smaller lung lesions than conventional X-rays. "But we don't know for sure that detecting a small lung cancer will actually reduce mortality from lung cancer," Aberle said. "Genetic and biological factors - not merely tumor size - determine whether a cancer spreads slowly or rapidly. Finding a small cancer on CT or chest X-ray is not necessarily the same as finding an early lung cancer." And there's another wrinkle. Most of the lung abnormalities detected with low-dose CT are ultimately found to be non-cancerous, yet individuals with positive screening results are faced with additional tests and procedures that carry risks and have emotional consequences. "At this time, we simply don't know whether using these technologies will do good or impose risk because of the medical interventions that follow," said Aberle. The primary goal of the NLST is to detect any differences in lung cancer deaths between those receiving chest X-ray and those receiving a CT scan. Study participants will be randomly assigned to either the chest X-ray group or the spiral CT group. Each volunteer will receive a baseline screening and two additional annual screenings using the same test, either X-ray or CT. All participants will be followed for an additional six to eight years at six to 12 month intervals to watch for any changes in their health status. "This study is important because there are more than 90 million current and former smokers in the U.S. at high risk for lung cancer. And death rates for this disease, unlike many other cancers, have not declined," said John Gohagan, a researcher in the NCI's Division of Cancer Prevention and the PLCO/NLST project officer. "Cigarette smoking is by far the most important risk factor in the development of lung cancer." Dr. Harmon Eyre, the American Cancer Society's chief medical officer and executive vice president for research and cancer control, agreed. "Reducing lung cancer deaths is a high priority for us," Eyre said. "We are committed to helping the National Cancer Institute reach full enrollment in this study as soon as possible." NLST Study volunteers will receive their screenings free. To qualify, volunteers need to meet these requirements: - Be current or former smokers aged 55 to 74. - Have never had lung cancer and have not had any cancer within the last five years. - Are not currently enrolled in any other cancer screening or prevention trial. - Have not had a CT scan of the chest or lungs within the last 18 months. In addition to the lung cancer screening study, some of the sites, including UCLA's Jonsson Cancer Center, also will be analyzing other critical measures of lung cancer screening effectiveness. These include the emotional and economic impacts of screening and the impact of the screening process itself on smoking behaviors. "These screening-related outcomes have not been systematically studied before and have important implications about the benefits of lung cancer screening as public policy," Aberle said. Additionally, UCLA's Jonsson Cancer Center and other study sites will collect and store samples of blood, urine, and sputum from study participants. These samples will provide an important resource for testing biological markers of lung cancer that might someday serve as screening tests themselves or might better help identify those at risk of getting lung cancer. For more information on NLST, please call the Jonsson Cancer Center's toll-free clinical trials hotline at 888-709-0719 or the National Cancer Institute's Cancer Information Service at 1-800-4-CANCER. For more information about UCLA's Jonsson Cancer Center, its people and resources, visit our web site at www.cancer.mednet.ucla.edu. For more information from the NCI, visit www.cancer.gov/NLST.

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